package edu.kaifadui.lmbase.jwt;

import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.exceptions.JWTVerificationException;
import edu.kaifadui.lmbase.pojo.Dev;
import edu.kaifadui.lmbase.service.DevService;
import edu.kaifadui.lmbase.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.util.CollectionUtils;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author dualseason
 */
public class AuthenticationInterceptor implements HandlerInterceptor {

    @Autowired
    private DevService devService;

    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object object) throws Exception {
        // 从 http 请求头中取出 token
        String token = httpServletRequest.getHeader("token");
        // 如果不是映射到方法直接通过
        if (!(object instanceof HandlerMethod)) {
            return true;
        }
        HandlerMethod handlerMethod = (HandlerMethod) object;
        Method method = handlerMethod.getMethod();
        // 检查是否有pass-token注释，有则跳过认证
        if (method.isAnnotationPresent(PassToken.class)) {
            PassToken passToken = method.getAnnotation(PassToken.class);
            if (passToken.required()) {
                return true;
            }
        }
        // 检查有没有需要用户权限的注解
        if (method.isAnnotationPresent(DevLoginToken.class)) {
            DevLoginToken devLoginToken = method.getAnnotation(DevLoginToken.class);
            if (devLoginToken.required()) {
                // 执行认证
                if (token == null) {
                    throw new RuntimeException("无token，请重新登录");
                }
                // 获取 token 中的 appkey
                String appkey;
                try {
                    appkey = JWT.decode(token).getAudience().get(0);
                } catch (JWTDecodeException j) {
                    throw new RuntimeException("401");
                }
                Map<String, Object> map = new HashMap<>(2);
                map.put("appkey",appkey);
                List<Dev> devs = devService.listByMap(map);
                if (CollectionUtils.isEmpty(devs)) {
                    throw new RuntimeException("用户不存在,请传入正确参数");
                }
                // 验证 token
                JWTVerifier jwtVerifier = JWT.require(Algorithm.HMAC256(devs.get(0).getAppsecret())).build();
                try {
                    jwtVerifier.verify(token);
                } catch (JWTVerificationException e) {
                    throw new RuntimeException("401");
                }
                return true;
            }
        }
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest,
                           HttpServletResponse httpServletResponse,
                           Object o, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest,
                                HttpServletResponse httpServletResponse,
                                Object o, Exception e) throws Exception {
    }
}